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Video transcript

We're asked to sort the following units of measurement into two categories: U.S. customary units and metric units. So these are just two different systems. You'll get more and more familiar with them. Then indicate whether each unit measures length, weight, mass, or volume. Let's do the first. Let's see which of these are U.S. customary unit versus metric units. So the liter is a metric unit. You would use it in the metric system. A gallon is a U.S. customary unit. We've been dealing with that. If you fill your gasoline in Europe, you're going to be filling it in terms of liters. In the U.S., you're going to be filling it in terms of gallons. And we're going to talk about whether they're units of volume and whatnot in a little bit. Decigram, that is metric system. In general, whenever you see these prefixes, deci, centi, kilo, you're dealing with the metric system. No one ever talks about a kilopound. I guess you could, but no one really talks about it. Same thing, millimeter. This is metric system. A gram is metric system. Meter is metric system. The foot is a U.S. customary unit. We'll talk about whether it's distance or any of that in a little bit. Kilogram, once again, it is metric units. In case you haven't gotten what I'm doing here, blue for metric, red for U.S. customary units, or I guess magenta. Centiliter, that is metric. Centimeter, meters are metric. And notice we have the prefix in both cases. Centi means 1/100. Cup, that is U.S. customary units. I have to do that in the magenta. Cup, U.S. customary units. Meter, that is the metric system. Pound, U.S. customary units. It's getting a little tedious. Inch, same thing, that's what we use in the U.S. Ounce, we use that in the U.S. And then the yard, we also use that in the U.S. Now we've divided them up. All the magenta ones are used in the U.S. All of the blue ones are used really in the rest of the world, and actually some places in the U.S. as well. I think a lot of the world is frustrated that the U.S., that we're not all converted to this because the metric system is actually a little bit more logical. It's easy to just figure out what it's saying, and we'll deal with that in more detail in the future. Now the next thing we to figure out is whether something is a measure of length, weight/mass-- and they're not exactly the same thing. Mass is how much of a substance you have. Weight is how much force with which gravity is pulling on that mass. And it would change depending on what planet you're on. But on Earth, they tend to be used interchangeably, so we'll use it roughly interchangeably here. And then you have volume, or how much space something takes up. So this is distance. This is moving in one dimension. Mass is how much stuff there is. Weight is how much the force that stuff is pulled on, on a planet, by gravity, or I guess a star anywhere. And volume is how much space does that stuff take up. Now let's think about it. Liter is volume. This right here is volume. How much space do you take up. Gallon is also volume. That's in the U.S. And in Europe, or in the metric system, it would be a liter. That's a gram. Gram is a unit of mass. So decigram just means 1/10 of a gram. Millimeter. Meter is a unit. Meter right here, that is the unit of distance or of length. Millimeter, milli means 1/1,000 of a meter. Foot, that is also a unit of length. Kilogram, that just means 1,000 grams. Kilo means a thousand. Gram, we already said, is a unit of mass. Centiliter, that means 1/100 of a liter. Liter, we already figured out, is a unit of volume. Centimeter, we already figured out. Meter is a unit of length. Centimeter means 1/100 of a meter. So this is a unit of length. Cup, we've seen multiple times already. It is a unit of volume, how much space does something take up. Meter, that is length. We've seen it multiple times already. Pound, that is actually a unit of weight. An inch is a unit of length. We're all familiar with it. An ounce-- you have to be careful here-- if someone just has an ounce, that is 1/16 of a pound. It as a unit of weight. If it was written fluid ounce, then we'd be talking about 1/16 of a pint, and then it would be a unit of volume. But since it's just ounce, it's a unit of weight, 1/16 of a pound. And then finally, a yard is a unit of length. And we are done.